Background: The aim of this study was to determine anatomical variations in the radiographic distance between the cemento-enamel junction and the alveolar crest with respect to ethnic heritage and gender in New Zealand dental students.

Methods: Digitized bitewing films of 123 second-year New Zealand dental students were examined with a computer imaging program on a desktop computer screen. The race of parents and grandparents was obtained by questionnaire.

Results: The mean distance from the cemento-enamel junction to the alveolar crest across the sample was 0.97 mm. Eighteen (14.6%) of the participants had measurements >2 mm, of whom 17 were Asians. Asians had a significantly larger mean distance than did non-Asians (1.10 mm compared to 0.83 mm; P <0.001). Gender was not a significant variable.

Conclusions: Students of Asian origin had a significantly greater distance between the cemento-enamel junction and the alveolar crest. It remains to be determined whether this is anatomical or disease related.